cianfa72's latest activity
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cianfa72 reacted to jbergman's post in the thread I Spacetime coordinate smoothness requirement with
Like.
Polar coordinates are not a valid chart for an open set ##U## containing the origin since the transition function with the identity... -
They will see stars if they look in the tangential direction (along the photon sphere), including multiple images of stars (including...
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cianfa72 reacted to PeterDonis's post in the thread B How to compare the proper times of two spatially distant mass points? with Like.
You can always compare the proper times of two objects if you have already determined which pair of events on each worldline you will...
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cianfa72 reacted to PeterDonis's post in the thread I A question about geodesics and notion of parallelism with Like.
In a curved manifold, vectors are not spacetime objects, they are objects in the tangent space at a point. So are tensors such as the...
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cianfa72 reacted to PeterDonis's post in the thread I Determining a stationary point of reference to base all absolute motion with
Agree.
All velocity is relative in relativity. It's just that, for timelike objects (objects like us and rocket ships), their velocity relative... -
cianfa72 replied to the thread A 1-Way Speed of Light.As @Ibix showed, the orthogonal grey grid lines in the diagram actually correspond/represent straight lines orthogonal in spacetime...
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@James Hasty - here's why all attempts to measure the one way speed of light fail. This is a Minkowski diagram - it shows the position...
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And the answer would depend on your assumptions, as always. Your error is in (a) assuming that the clocks are initially synchronised...
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He defined time in a particular kind of coordinate chart (an inertial chart with orthogonal axes) that way. But that definition is...
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No it doesn't! That's the point! No, you're approximately using Rindler coordinates.
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cianfa72 replied to the thread A 1-Way Speed of Light.I'd add the qualifier coordinate speed in both SR and GR is invariant in inertial frames since the 4-velocity of light, like any...
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The two way speed of light is only guaranteed to be invariant for inertial observers. Your apparatus is not inertial. The difference...
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cianfa72 replied to the thread I Conventionality of the One-Way Speed of Light.In the above, I believe the only sensibile way to check/ensure what I highlighted in bold, is to use light beams sent forth and back...
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Worth noting that you'll get different two way speeds of light in the vertical configuration depending on which clock you use. If you...
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No, it won't. Ideally it will be 180 degrees, since A and B are on opposite sides of the wheel. No, opposite directions. No, they...